Regimens for immunisation with meningococcal conjugates

ABSTRACT

Multivalent meningococcal conjugate vaccines are administered according to a schedule in which a first dose is administered to a patient aged between 0 and 12 months, and a second dose is administered to the patient aged between 12 and 24 months.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No. 16/716,638 filed on Dec. 17, 2019, which is a Continuation of U.S. application Ser. No. 12/225,501 filed on May 18, 2009 (now U.S. Pat. No. 10,543,265 issued Jan. 28, 2020), which is a U.S. National Phase of PCT/US2007/007115 filed on Mar. 22, 2007, which claims the benefit of U.S. Provisional Application No. 60/785,234, filed Mar. 22, 2006, the disclosures of which are incorporated herein by reference in their entirety for all purposes.

TECHNICAL FIELD

This invention is in the field of immunising patients with meningococcal conjugates.

BACKGROUND OF THE INVENTION

Conjugate vaccines for N. meningitidis serogroup C have been approved for human use, and include the products known as Menjugate™ [1], Meningitec™ and NeisVac-C™. Bivalent mixtures of conjugates from serogroups A+C [2,3] and C+Y [4] have also been reported. Mixtures of conjugates from all four of serogroups A, C, W135 and Y are also known (e.g. see references 5-9), including the Menactra™ product that was licensed in 2005.

In addition to the antigens included in a vaccine, an important aspect of effective immunisation is the dosing schedule. As noted in chapter 8 of reference 10, “most vaccines require administration of multiple doses in a primary series for development of immunity”. Moreover, “periodic revaccination (‘booster doses’) with certain vaccines may be necessary to maintain immunity”.

Known schedules for serogroup C meningococcal conjugate vaccines include: a single dose at 12 months of age; two doses at 2 & 4 months; three doses at 2, 3 & 4 months of age; three doses at 2, 4 & 6 months of age; three doses at 3, 5 & 12 months of age; three doses at 2, 4 & 12 months. Alternative schedules, including the potential for a dose in late infancy or the second year of life, have been suggested [11].

Multivalent meningococcal conjugate combinations have been administered according to various dosing schedules. For example, known single-dose schedules for multivalent meningococcal conjugate vaccines include: at 14 weeks of age [12]; at 6 months of age [13]; at 9 months [12]; between 12-16 months [14]; between 2-3 years of age [5,15]; between 2-10 years [16,17,18]; between 11-18 years [18]; 18-50 years [19]; 18-55 years [18]. The prescribing information for Menactra™ shows that it is administered as a single dose in 11-18 or 18-55 year olds.

Known 2-dose schedules for multivalent meningococcal conjugate vaccines include: 2 & 6 months of age [13]; first dose at 14 weeks of age, second dose at 9 months of age [12]; first dose at 12-15 months, second dose 2 months later [5]; first dose at 12-16 months, second dose 1 month later [14]; doses in 2 year olds at time zero and then 2 months later [18]; in adults at time zero and then 6 weeks later [2]; in adults at time zero and then 2 months later [3]. A clinical study has also been reported in which patients received a first dose aged 11-18 years and a second dose 3 years later.

Known 3-dose schedules for multivalent meningococcal conjugate vaccines include: 6, 10 and 14 weeks of age [5,12]; 2, 3 & 4 months [13]; 2, 4 & 6 months of age [18]; 3, 4 & 5 months of age [20].

A 4-dose schedule at 6 weeks, 10 weeks, 14 weeks and 9 months is disclosed in reference 12.

It is an object of the invention to provide further and improved schedules for administering multivalent meningococcal conjugate vaccines, in particular to children.

DISCLOSURE OF THE INVENTION

According to the invention, multivalent meningococcal conjugate vaccines are administered according to a schedule in which a first dose is administered to a patient aged between 0 and 12 months, and a second dose is administered to a patient aged between 12 and 24 months. This schedule offers early protection than the existing licensed schedule, reduces the cost of immunisation by avoiding the need for a third immunisation, and the second dose can act as a booster dose for providing long-lasting protection.

Thus the invention provides a method for immunising a patient, comprising: (a) administering a multivalent meningococcal conjugate vaccine to the patient when they are aged between 0 and 12 months; and (b) administering a multivalent meningococcal conjugate vaccine to the patient when they are aged between 12 and 24 months.

The invention also provides a method for immunising a patient who previously received a multivalent meningococcal conjugate vaccine to the patient when they were aged between 0 and 12 months, comprising: administering a multivalent meningococcal conjugate vaccine to the patient when they are aged between 12 and 24 months.

The invention also provides the use of a plurality of meningococcal conjugates in the manufacture of a medicament for administering to a patient in an immunisation schedule comprising: (a) administering the medicament to the patient when they are aged between 0 and 12 months; and (b) administering the medicament to the patient when they are aged between 12 and 24 months.

The invention also provides the use of a plurality of meningococcal conjugates in the manufacture of a medicament for administering to a patient who is aged between 12 and 24 months and who previously received a multivalent meningococcal conjugate vaccine when they were aged between 0 and 12 months.

The invention also provides a kit comprising: (a) a multivalent meningococcal conjugate vaccine; and (b) instructions for administering the vaccine according to a schedule that includes: (a) first administering the vaccine to a patient when they are aged between 0 and 12 months; and (b) then administering the vaccine to a patient when they are aged between 12 and 24 months.

The Schedule

The schedule of the invention involves a first dose in the first year of life and a second dose in the second year of life. The first dose is given to a patient aged between 0 and 12 months, up to but not including their first birthday. The second dose is given to a patient aged 12 and 24 months, starting on the day of their first birthday, up to and including their second birthday.

Within this overall schedule, the two doses can be administered at any time. In general, however, the two doses will be administered at least 4 weeks apart e.g. ≥8 weeks apart, ≥2 months apart, ≥3 months apart, ≥6 months apart, etc.

Within the 0-12 month period, the first dose is preferably not administered before about 6 weeks of age. after 5 weeks. Typical times for receiving the first dose are at 2 months, 3 months, 4 months, 5 months or 6 months of age.

Within the 12-24 month period, the second dose is preferably administered in the first half i.e. between 12 and 18 months e.g. between 12 and 15 months of age, or between 15 and 18 months.

The patient will not have received a meningococcal conjugate vaccine before the first dose in the schedule. In preferred embodiments, the patient does not receive a meningococcal conjugate vaccine between the first dose and the second dose, but sometimes an intermediate dose may be administered. For example, the patient may receive 2 or 3 doses in the 0-12 month period e.g. at 2, 3 & 4 months of age, at 3, 4 & 5 months of age, at 2, 4 & 6 months, at 3, 5 & 9 months etc.

In some embodiments, the patient does not receive a further dose, but in other embodiments they can do so. Such a further dose is preferably not administered until after the patient's second birthday e.g. until after their fifth birthday, after their tenth birthday, after their fifteenth birthday, after their seventeenth birthday, after their twenty-first birthday, etc. The further dose may be administered when circulating antibody levels have declined to undetectable levels [21].

Conveniently, the first dose can be administered at substantially the same time as (e.g. during the same medical consultation or visit to a healthcare professional) another vaccine e.g. at substantially the same time as a hepatitis B virus vaccine, a diphtheria vaccine, a tetanus vaccine, a pertussis vaccine (either cellular or, preferably, acellular), a Haemophilus influenzae type b vaccine, a Streptococcus pneumoniae vaccine, and/or a polio vaccine (preferably in inactivated poliovirus vaccine). Each of these optionally co-administered vaccines may be a monovalent vaccine or may be part of a combination vaccine (e.g. as part of a D-T-P vaccine).

Conveniently, the second dose can be administered at substantially the same time as (e.g. during the same medical consultation or visit to a healthcare professional) another vaccine e.g. at substantially the same time as a hepatitis B virus vaccine, a diphtheria vaccine, a tetanus vaccine, a pertussis vaccine (either cellular or acellular), a Haemophilus influenzae type b vaccine, a Streptococcus pneumoniae vaccine, a polio vaccine (preferably in inactivated poliovirus vaccine), an influenza vaccine, a chickenpox vaccine, a measles vaccine, a mumps vaccine, and/or a rubella vaccine. Each of these optionally co-administered vaccines may be a monovalent vaccine or may be part of a combination vaccine (e.g. as part of a M-M-R vaccine).

The Vaccine

The invention involves the administration of multivalent meningococcal conjugate vaccines i.e. vaccines that, when administered, simultaneously provide immunity against 2, 3, 4 or more different serotypes of N. meningitidis. Multivalent vaccines against 2, 3, or 4 of serogroups A, C, W135 and Y are preferred e.g. A+C, C+Y, W135+Y, A+W135+Y, A+C+W135+Y, etc. Vaccines including at least serogroup C are preferred (e.g. A+C), and vaccines including saccharides from all four of serogroups A, C, W135 and Y are most preferred.

The vaccines include a meningococcal capsular saccharide conjugated to a carrier protein.

The capsular saccharide of serogroup A meningococcus is a homopolymer of (α1→6)-linked N-acetyl-D-mannosamine-1-phosphate, with partial O-acetylation in the C3 and C4 positions. The acetyl groups can be replaced with blocking groups to prevent hydrolysis [22], and such modified saccharides are still serogroup A saccharides within the meaning of the present invention. The serogroup C capsular saccharide is a homopolymer of (α2→9)-linked sialic acid (N-acetyl neuraminic acid, or ‘NeuNAc’). Most serogroup C strains have O-acetyl groups at C-7 and/or C-8 of the sialic acid residues, but about 15% of clinical isolates lack these O-acetyl groups [23,24]. The saccharide structure is written as →9)-Neu p NAc 7/8 OAc-(α2→. The serogroup W135 saccharide is a polymer of sialic acid-galactose disaccharide units. Like the serogroup C saccharide, it has variable O-acetylation, but at sialic acid 7 and 9 positions [25]. The structure is written as: →4)-D-Neup5Ac(7/9OAc)-α-(2→6)-D-Gal-α-(1→. The serogroup Y saccharide is similar to the serogroup W135 saccharide, except that the disaccharide repeating unit includes glucose instead of galactose. Like serogroup W135, it has variable O-acetylation at sialic acid 7 and 9 positions [25]. The serogroup Y structure is written as:→4)-D-Neup5Ac(7/9OAc)-α-(2→6)-D-Glc-α-(1→.

The saccharides used according to the invention may be O-acetylated as described above (e.g. with the same O-acetylation pattern as seen in native capsular saccharides), or they may be partially or totally de-O-acetylated at one or more positions of the saccharide rings, or they may be hyper-O-acetylated relative to the native capsular saccharides. Serogroup C saccharides used with the invention may be prepared from either OAc+ or OAc− strains. Preferred strains for production of serogroup C conjugates are OAc+ strains, preferably of serotype 16, preferably of serosubtype P1.7a,1. Thus C:16:P1.7a,1 OAc+ strains are preferred. Preferably at least 50% (e.g. at least 60%, 70%, 80%, 90%, 95% or more) of the mannosamine residues in a serogroup A saccharides are O-acetylated at the C-3 position.

The saccharide moieties in conjugates may comprise full-length saccharides as prepared from meningococci, and/or it may comprise fragments of full-length saccharides. The saccharides used according to the invention are preferably shorter than the native capsular saccharides seen in bacteria. Thus the saccharides are preferably depolymerised, with depolymerisation occurring during or after saccharide purification but before conjugation. Depolymerisation reduces the chain length of the saccharides. One depolymerisation method involves the use of hydrogen peroxide [5]. Hydrogen peroxide is added to a saccharide (e.g. to give a final H₂O₂ concentration of 1%), and the mixture is then incubated (e.g. at about 55° C.) until a desired chain length reduction has been achieved. Another depolymerisation method involves acid hydrolysis [5]. Other depolymerisation methods are known in the art. The saccharides used to prepare conjugates for use according to the invention may be obtainable by any of these depolymerisation methods. Depolymerisation can be used in order to provide an optimum chain length for immunogenicity and/or to reduce chain length for physical manageability of the saccharides. Preferred saccharides have the following range of average degrees of polymerisation (Dp): A=10-20; C=12-22; W135=15-25; Y=15-25. In terms of molecular weight, rather than Dp, preferred ranges are, for all serogroups: <100 kDa; 5 kDa-75 kDa; 7 kDa-50 kDa; 8 kDa-35 kDa; 12 kDa-25 kDa; 15 kDa-22 kDa.

Typical carrier proteins for use in conjugates are bacterial toxins, such as diphtheria toxin [e.g. see chapter 13 of ref 10; refs. 26-29] (or its CRM197 mutant [30-33]) and tetanus toxin, usually in toxoid form (e.g. obtained by treatment with an inactivating chemical, such as formalin or formaldehyde). Other suitable carrier proteins include, but are not limited to, N. meningitidis outer membrane protein [34], synthetic peptides [35,36], heat shock proteins [37,38], pertussis proteins [39,40], cytokines [41], lymphokines [41], hormones [41], growth factors [41], artificial proteins comprising multiple human CD4⁺ T cell epitopes from various pathogen-derived antigens [42] such as N19 [43], protein D from H. influenzae [44-46], pneumolysin [47], pneumococcal surface protein PspA [48], iron-uptake proteins [49], toxin A or B from C. difficile [50], etc.

Four particularly preferred carrier proteins are diphtheria toxoid (Dt), tetanus toxoid (Tt), CRM197 and protein D from H. influenzae. These proteins are preferred because they are the main carriers currently in use in pediatric vaccines e.g. the Hib conjugates from GSK use Tt as the carrier, the HibTITER™ product uses CRM197, the pneumococcal conjugates in Prevenar™ use CRM197, the Menjugate™ and Meningitec™ products use CRM197, and NeisVac-C™ uses Tt.

Conjugates are preferably mixed at substantially equal masses (measured as mass of saccharide) e.g. the mass of each serogroup's saccharide is within ±10% of each other. A typical quantity of meningococcal antigen per serogroup in a composition is between 1 μg and 20 μg e.g. between 2 and 10 μg per serogroup, or about 4 μg. As an alternative to an equal ratio, a double serogroup A dose may be used.

Conjugates with a saccharide:protein ratio (w/w) of between 1:15 (i.e. excess protein) and 15:1 (i.e. excess saccharide), preferably between 1:5 and 5:1, are preferred. Excess carrier protein is preferred. Conjugates with saccharide:protein ratio of about 1:12 or about 1:3 are preferred, particularly where the carrier is Dt.

Any suitable conjugation reaction can be used, with any suitable linker where necessary.

The saccharide will typically be activated or functionalised prior to conjugation. Activation may involve, for example, cyanylating reagents [51, 52, etc.]). Other suitable techniques use active esters, carbodiimides, hydrazides, norborane, p-nitrobenzoic acid, N-hydroxysuccinimide, S—NHS, EDC, TSTU; see also the introduction to reference 53).

Linkages via a linker group may be made using any known procedure, for example, the procedures described in references 54 and 55. One type of linkage involves reductive amination of the polysaccharide, coupling the resulting amino group with one end of an adipic acid linker group, and then coupling a protein to the other end of the adipic acid linker group [56, 57, 58]. Other linkers include B-propionamido [59], nitrophenyl-ethylamine [60], haloacyl halides [61], glycosidic linkages [62], 6-aminocaproic acid [63], ADH [64], C4 to C12 moieties [65] etc. As an alternative to using a linker, direct linkage can be used. Direct linkages to the protein may comprise oxidation of the polysaccharide followed by reductive amination with the protein, as described in, for example, references 66 and 67.

A preferred conjugation process involves: introduction of amino groups into the saccharide (e.g. by replacing terminal ═O groups with —NH₂) followed by derivatisation with an adipic diester (e.g. adipic acid N-hydroxysuccinimide diester) and reaction with carrier protein (e.g. CRM197). Further details of this conjugation method can be found in reference 6. Conjugates obtainable by this method are preferred conjugates for use according to the invention.

In another preferred conjugation process, a saccharide is reacted with adipic acid dihydrazide. For serogroup A, carbodiimide (EDAC) may also be added at this stage. After a reaction period, sodium cyanoborohydride is added. Derivatised saccharide can then be prepared e.g. by ultrafiltration. The derivatized saccharide is then mixed with carrier protein (e.g. with a diphtheria toxoid), and carbodiimide is added. After a reaction period, the conjugate can be recovered. Further details of this conjugation method can be found in reference 6. Conjugates obtainable by this method are preferred conjugates for use according to the invention e.g. conjugates comprising a diphtheria toxoid carrier and an adipic acid linker.

In another preferred conjugation process, a saccharide is derivatised with a cyanylating reagent [52], followed by coupling to a protein (direct, or after introduction of a thiol or hydrazide nucleophile group into the carrier), without the need to use a linker. Suitable cyanylating reagents include 1-cyano-4-(dimethylamino)-pyridinium tetrafluoroborate (‘CDAP’), p-nitrophenylcyanate and N-cyanotriethylammonium tetrafluoroborate (‘CTEA’). CDAP is preferred, particularly where H. influenzae protein D is the common carrier. Direct coupling is preferred.

Administration of a conjugate preferably results in an increase in serum bactericidal assay (SBA) titre for the relevant serogroup of at least 4-fold, and preferably at least 8-fold, measured with human complement [68]. If rabbit complement is used to measure SBA titres then the titre increase is preferably at least 128-fold.

Conjugates are preferably prepared separately and then mixed. Thus it is preferred not to use a single protein carrying multiple serogroups (cf. references 69 & 70). After mixing, the concentration of the mixed conjugates can be adjusted e.g. with sterile pyrogen-free, phosphate-buffered saline.

In compositions of the invention, the amount of carrier (conjugated and unconjugated) from each conjugate is preferably no more than 100 μg/ml e.g. <30 μg/ml of carrier protein from each conjugate. Preferred compositions include a total concentration of carrier (either solely for the combined meningococcal conjugates, or preferably for the composition as a whole) of less than 500 μg/ml e.g. <400 μg/ml, <300 μg/ml, <200 μg/ml, <100 μg/ml, <50 μg/ml, etc.

Vaccines of the invention may include no antigens other than the meningococcal conjugates. In some embodiments, however, vaccines may include further antigens. Thus they may include further antigens from other pathogens, particularly from bacteria and/or viruses. They may include other conjugated saccharides from non-meningococcal organisms and/or they may include non-saccharide antigens. For example, they may include one or more of the following:

-   -   a diphtheria toxoid (‘D’).     -   a tetanus toxoid (‘T’).     -   a pertussis antigen (‘P’), which is typically acellular Can.     -   a hepatitis B virus (HBV) surface antigen (‘HBsAg’).     -   a hepatitis A virus (HAV) antigen.     -   a conjugated Haemophilus influenzae type b capsular saccharide     -   a protein from serogroup B of N. meningitidis.     -   an vesicle preparation from serogroup B of N. meningitidis.     -   inactivated poliovirus vaccine (IPV).

The schedule of the invention may use different vaccines for the first and second doses e.g. the first vaccine may include non-meningococcal antigens whereas the second vaccine does not, or the first vaccine may include a first set of non-meningococcal antigens (e.g. DTP) whereas the second vaccine includes a second (different) set of non-meningococcal antigens (e.g. MMR).

In addition to the antigenic components described above, compositions of the invention will generally include a non-antigenic component. The non-antigenic component can include carriers, adjuvants, excipients, buffers, etc., as described in more detail below. These non-antigenic components may have various sources. For example, they may be present in one of the antigen or adjuvant materials that is used during manufacture or may be added separately from those components. Preferred compositions of the invention include one or more pharmaceutical carrier(s) and/or excipient(s). A thorough discussion of pharmaceutically acceptable carriers and excipients is available in reference 71.

To control tonicity, it is preferred to include a physiological salt, such as a sodium salt. Sodium chloride (NaCl) is preferred, which may be present at between 1 and 20 mg/ml.

Compositions will generally have an osmolality of between 200 mOsm/kg and 400 mOsm/kg, preferably between 240-360 mOsm/kg, and will more preferably fall within the range of 290-310 mOsm/kg. Osmolality has previously been reported not to have an impact on pain caused by vaccination [72], but keeping osmolality in this range is nevertheless preferred.

Compositions of the invention may include one or more buffers. Typical buffers include: a phosphate buffer; a Tris buffer; a borate buffer; a succinate buffer; a histidine buffer; or a citrate buffer. Buffers will typically be included in the 5-20 mM range.

The pH of a composition of the invention will generally be between 5.0 and 7.5, and more typically between 5.0 and 6.0 for optimum stability, or between 6.0 and 7.0.

Compositions of the invention are preferably sterile.

Compositions of the invention are preferably non-pyrogenic e.g. containing <1 EU (endotoxin unit, a standard measure) per dose, and preferably <0.1 EU per dose.

Compositions of the invention are preferably gluten free.

Where antigens are adsorbed, a composition may be a suspension with a cloudy appearance. This appearance means that microbial contamination is not readily visible, and so the vaccine preferably contains a preservative. This is particularly important when the vaccine is packaged in multidose containers. Preferred preservatives for inclusion are 2-phenoxyethanol and thimerosal. It is recommended, however, not to use mercurial preservatives (e.g. thimerosal) where possible. It is preferred that compositions of the invention contain less than about 25 ng/ml mercury.

The concentration of any aluminium salts in a composition of the invention, expressed in terms of Al³⁺, is preferably less than 5 mg/ml e.g. ≤4 mg/ml, ≤3 mg/ml, ≤2 mg/ml, ≤1 mg/ml, etc.

Compositions of the invention are preferably administered to patients in 0.5 ml doses. References to 0.5 ml doses will be understood to include normal variance e.g. 0.5 ml±0.05 ml.

Residual material from individual antigenic components may also be present in trace amounts in the final vaccine produced by the process of the invention. For example, if formaldehyde is used to prepare the toxoids of diphtheria, tetanus and pertussis then the final vaccine product may retain trace amounts of formaldehyde (e.g. less than 10 μg/ml, preferably <5 μg/ml). Media or stabilizers may have been used during poliovirus preparation (e.g. Medium 199), and these may carry through to the final vaccine. Similarly, free amino acids (e.g. alanine, arginine, aspartate, cysteine and/or cystine, glutamate, glutamine, glycine, histidine, proline and/or hydroxyproline, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine and/or valine), vitamins (e.g. choline, ascorbate, etc.), disodium phosphate, monopotassium phosphate, calcium, glucose, adenine sulfate, phenol red, sodium acetate, potassium chloride, etc. may be retained in the final vaccine at ≤100 μg/ml, preferably <10 μg/ml, each. Other components from antigen preparations, such as neomycin (e.g. neomycin sulfate, particularly from an IPV component), polymyxin B (e.g. polymyxin B sulfate, particularly from an IPV component), etc. may also be present e.g. at sub-nanogram amounts per dose.

A further possible component of the final vaccine which originates in the antigen preparations arises from less-than-total purification of antigens. Small amounts of B. pertussis, C. diphtheriae, C. tetani and/or S. cerevisiae proteins and/or genomic DNA may therefore be present.

Meningococcal conjugates may be lyophilised prior to use according to the invention. If lyophilised, the composition may include a stabiliser such as mannitol. It may also include sodium chloride.

The Patient

The age of patients receiving vaccines of the invention is dictated by the schedule.

Although the patient will not have received a meningococcal conjugate vaccine before the first dose in the schedule, they may have received other non-meningococcal conjugates and/or they may have received the carrier protein that is used in the meningococcal conjugate. Prior exposure to the carrier may have been as carrier in non-meningococcal conjugate (e.g. in a Hib conjugate) and/or as antigen itself (e.g. tetanus toxoid is commonly used as carrier for Hib conjugates, but is also used as an antigen for protecting against C. tetani).

After receiving the first dose in the schedule, and before the second dose, a patient is distinguishable from a person in the general population, as they will have mounted an immune response against the first dose. Thus patients waiting to receive the schedule's second dose are a specific and identifiable subset of the population.

Compositions of the invention can be administered by intramuscular injection e.g. into the arm, leg or buttock. Where another vaccine is co-administered then it is typical to inject compositions into opposite limbs e.g. to inject one into the left arm and one into the right arm.

Where compositions of the invention include an aluminium-based adjuvant, settling of components may occur during storage. The composition should therefore be shaken prior to administration to a patient. The shaken composition will generally be a turbid white suspension.

The patient is a human.

Packaging

Vaccines for use with the invention can be placed into containers for use. Suitable containers include vials and disposable syringes (preferably sterile ones).

Where a composition of the invention is packaged into vials, these are preferably made of a glass or plastic material. The vial is preferably sterilized before the composition is added to it. To avoid problems with latex-sensitive patients, vials are preferably sealed with a latex-free stopper. The vial may include a single dose of vaccine, or it may include more than one dose (a ‘multidose’ vial) e.g. 10 doses. When using a multidose vial, each dose should be withdrawn with a sterile needle and syringe under strict aseptic conditions, taking care to avoid contaminating the vial contents. Preferred vials are made of colorless glass.

A vial can have a cap (e.g. a Luer lock) adapted such that a pre-filled syringe can be inserted into the cap, the contents of the syringe can be expelled into the vial (e.g. to reconstitute lyophilised material therein), and the contents of the vial can be removed back into the syringe. After removal of the syringe from the vial, a needle can then be attached and the composition can be administered to a patient. The cap is preferably located inside a seal or cover, such that the seal or cover has to be removed before the cap can be accessed.

Where the composition is packaged into a syringe, the syringe will not normally have a needle attached to it, although a separate needle may be supplied with the syringe for assembly and use. Safety needles are preferred. 1-inch 23-gauge, 1-inch 25-gauge and ⅝-inch 25-gauge needles are typical. Syringes may be provided with peel-off labels on which the lot number and expiration date of the contents may be printed, to facilitate record keeping. The plunger in the syringe preferably has a stopper to prevent the plunger from being accidentally removed during aspiration. The syringes may have a latex rubber cap and/or plunger. Disposable syringes contain a single dose of vaccine. The syringe will generally have a tip cap to seal the tip prior to attachment of a needle, and the tip cap is preferably made of butyl rubber. If the syringe and needle are packaged separately then the needle is preferably fitted with a butyl rubber shield. Grey butyl rubber is preferred. Preferred syringes are those marketed under the trade name “Tip-Lok”™.

Where a glass container (e.g. a syringe or a vial) is used, then it is preferred to use a container made from a borosilicate glass rather than from a soda lime glass.

If a vaccine is in lyophilised form then it will usually be resuspended into an aqueous form prior to administration.

In addition to containing vaccines for administration, kits of the invention can include instructions for administering the vaccine. The instructions will refer to an immunisation schedule that includes: (a) first administering the vaccine to a patient when they are aged between 0 and 12 months; and (b) then administering the vaccine to a patient when they are aged between 12 and 24 months.

Adjuvants

Vaccines of the invention may include an adjuvant. Where a vaccine includes only meningococcal conjugates, however, use of an adjuvant is not preferred. Where an adjuvant is used, it may comprise one or more aluminium salts, and particularly an aluminium phosphate adjuvant and/or an aluminium hydroxide adjuvant.

Aluminium adjuvants currently in use are typically referred to either as “aluminium hydroxide” or as “aluminium phosphate” adjuvants. These are names of convenience, however, as neither is a precise description of the actual chemical compound which is present (e.g. see chapter 9 of reference 73). The invention can use any of the “hydroxide” or “phosphate” salts that are in general use as adjuvants.

The adjuvants known as “aluminium hydroxide” are typically aluminium oxyhydroxide salts, which are usually at least partially crystalline. Aluminium oxyhydroxide, which can be represented by the formula AlO(OH), can be distinguished from other aluminium compounds, such as aluminium hydroxide Al(OH)₃, by infrared (IR) spectroscopy, in particular by the presence of an adsorption band at 1070 cm⁻¹ and a strong shoulder at 3090-3100 cm⁻¹ (chapter 9 of ref. 73).

The adjuvants known as “aluminium phosphate” are typically aluminium hydroxyphosphates, often also containing a small amount of sulfate. They may be obtained by precipitation, and the reaction conditions and concentrations during precipitation can influence the degree of substitution of phosphate for hydroxyl in the salt. Hydroxyphosphates generally have a PO₄/Al molar ratio between 0.3 and 0.99. Hydroxyphosphates can be distinguished from strict AlPO₄ by the presence of hydroxyl groups. For example, an IR spectrum band at 3164 cm⁻¹ (e.g. when heated to 200° C.) indicates the presence of structural hydroxyls (chapter 9 of ref. 73).

The PO₄/Al³⁺ molar ratio of an aluminium phosphate adjuvant will generally be between 0.3 and 1.2, preferably between 0.8 and 1.2, and more preferably 0.95±0.1. The aluminium phosphate will generally be amorphous, particularly for hydroxyphosphate salts. A typical adjuvant is amorphous aluminium hydroxyphosphate with PO₄/Al molar ratio between 0.84 and 0.92, included at 0.6 mg Al³⁺/ml. The aluminium phosphate will generally be particulate. Typical diameters of the particles are in the range 0.5-20 μm (e.g. about 5-10 μm) after any antigen adsorption.

The PZC of aluminium phosphate is inversely related to the degree of substitution of phosphate for hydroxyl, and this degree of substitution can vary depending on reaction conditions and concentration of reactants used for preparing the salt by precipitation. PZC is also altered by changing the concentration of free phosphate ions in solution (more phosphate=more acidic PZC) or by adding a buffer such as a histidine buffer (makes PZC more basic). Aluminium phosphates used according to the invention will generally have a PZC of between 4.0 and 7.0, more preferably between 5.0 and 6.5 e.g. about 5.7.

An aluminium phosphate solution used to prepare a composition of the invention may contain a buffer (e.g. a phosphate or a histidine or a Tris buffer), but this is not always necessary. The aluminium phosphate solution is preferably sterile and pyrogen-free. The aluminium phosphate solution may include free aqueous phosphate ions e.g. present at a concentration between 1.0 and 20 mM, preferably between 5 and 15 mM, and more preferably about 10 mM. The aluminium phosphate solution may also comprise sodium chloride. The concentration of sodium chloride is preferably in the range of 0.1 to 100 mg/ml (e.g. 0.5-50 mg/ml, 1-20 mg/ml, 2-10 mg/ml) and is more preferably about 3±1 mg/ml. The presence of NaCl facilitates the correct measurement of pH prior to adsorption of antigens.

A mixture of both an aluminium hydroxide adjuvant and an aluminium phosphate adjuvant can be used. If so, there may be more aluminium phosphate than hydroxide e.g. a weight ratio of at least 2:1 e.g. ≥5:1, ≥6:1, ≥7:1, ≥8:1, ≥9:1, etc.

General

The term “comprising” encompasses “including” as well as “consisting” e.g. a composition “comprising” X may consist exclusively of X or may include something additional e.g. X+Y.

The word “substantially” does not exclude “completely” e.g. a composition which is “substantially free” from Y may be completely free from Y. Where necessary, the word “substantially” may be omitted from the definition of the invention.

The term “about” in relation to a numerical value x means, for example, x±10%.

Unless specifically stated, a process comprising a step of mixing two or more components does not require any specific order of mixing. Thus components can be mixed in any order. Where there are three components then two components can be combined with each other, and then the combination may be combined with the third component, etc.

Where an antigen is described as being “adsorbed” to an adjuvant, it is preferred that at least 50% (by weight) of that antigen is adsorbed e.g. 50%, 60%, 70%, 80%, 90%, 95%, 98% or more. It is preferred that diphtheria toxoid and tetanus toxoid are both totally adsorbed i.e. none is detectable in supernatant. Total adsorption of HBsAg is also preferred.

Amounts of conjugates are generally given in terms of mass of saccharide (i.e. the dose of the conjugate (carrier+saccharide) as a whole is higher than the stated dose) in order to avoid variation due to choice of carrier.

Where animal (and particularly bovine) materials are used in the culture of cells, they should be obtained from sources that are free from transmissible spongiform encaphalopathies (TSEs), and in particular free from bovine spongiform encephalopathy (BSE).

MODES FOR CARRYING OUT THE INVENTION

The immunogenicity, safety, tolerability and the ability to prime for memory of a meningococcal conjugate vaccine are investigated in a multi-centre, open-label, controlled, randomized study. Infants are split into three groups to receive an unadjuvanted 4-valent conjugated A-C-W135-Y vaccine as follows, with the group 1 schedule being an embodiment of the invention:

-   -   1: first doses at about 6 months, then a second dose at about 12         months (on or after birthday)     -   2: single dose at about 12 months (on or after birthday)     -   3: dose of monovalent MenC at 12 months, then 4-valent at 18         months.

Meningococcal conjugates are administered at the same time as other routine pediatric vaccines, and blood samples for serological analysis are taken both at the time of vaccination and 1 month later:

Visit 1 Visit 2 Visit 3 Visit 4 Group 1 6 months 7 months 12 months 13 months B, M4, PC7, 5 B B, M4, PC7 B, 4V Group 2 6 months 7 months 12 months 13 months B, PC7, 5 B B, M4, PC7 B, 4V Group 3 12 months 13 months 18 months 19 months B, M1, PC7 B, 4V B, M4, 5 B Key: B = blood taken for serology; 5 = D-T-Pa-Hib-IPV; PC7 = 7-valent pneumococcal conjugate; 4V = MMR + V; M4 = 4-valent Men-A-C-W135-Y conjugates; M1 = Men-C conjugate.

Immunogenicity is assessed by evaluating serum antibody responses by measuring bactericidal antibody titers.

For blood samples taken at the first 2 visits, the bactericidal antibody titer at visit 2, expressed as a ratio relative to visit 1, was as follows for each group:

A C W135 Y Group 1 1.5 11 2.8 1.8 Group 2 1.0 1 1.0 1.0 Group 3 1.0 20 1.0 1.0

It will be understood that the invention has been described by way of example only, and that modifications may be made whilst remaining within the scope and spirit of the invention.

REFERENCES

(the contents of which are hereby incorporated by reference)

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1. A kit comprising: (a) a multivalent meningococcal capsular saccharide-carrier protein conjugate vaccine; and (b) instructions for administering the vaccine according to a schedule that includes: (a) first administering the vaccine to a patient when said patient is about 6 months of age; and (b) then administering the vaccine to the patient when said patient is about 12 months of age, wherein the multivalent meningococcal capsular saccharide-carrier protein conjugate vaccine includes capsular saccharide-carrier protein conjugates of at least meningococcal serogroups A, C, W135 and Y.
 2. The kit of claim 1, wherein the carrier protein is selected from diphtheria toxoid and CRM197.
 3. The kit of claim 1, wherein the multivalent meningococcal capsular saccharide-carrier protein conjugate vaccine is unadjuvanted.
 4. The kit of claim 1, wherein the multivalent meningococcal capsular saccharide-carrier protein conjugate vaccine is adjuvanted.
 5. The kit of claim 1, wherein the schedule includes: (a) first administering the vaccine to a patient when said patient is 6 months of age.
 6. The kit of claim 1, wherein the schedule includes: (b) administering the vaccine to the patient when said patient is about 12 months of age.
 7. The kit of claim 1, wherein the schedule includes: (a) first administering the vaccine to a patient when said patient is 6 months of age; and (b) then administering the vaccine to the patient when said patient is 12 months of age. 